In industrial printing systems it is common to print on rolls or webs of substrates. Use of webs facilitates high-speed and high volume printing.
In inkjet printing systems the printheads are contactless in that they do not come into direct contact with the substrate on which they are printing. A small gap, typically in the order of one or several millimeters, is maintained between the printheads and the substrate. Ink drops or other liquids are ejected from printhead nozzles across the gap to a substrate where they form part of a printed image. In the event that the size of the gap is not maintained during a printing operation damage may occur to the substrate causing print quality issues. In some situations a printhead may become irreplaceably damaged if it contacts a substrate.
Printing systems typically rely on being used with substrates conforming to a minimum set of manufacturer recommended characteristics. Characteristics may include, for example, the material of the substrate, the thickness of the substrate, the straightness of the substrate, and the like. Use of manufacturer recommended substrates helps ensure correct operation of the printing system, and further helps to reduce image quality problems.
There has recently, however, been a push by users to use cheaper substrates whose characteristics may not conform to manufacturer's substrate recommendations. Use of such substrates poses a real risk of image quality issues or printer damage occurring.